Printed board with component mounting pin

ABSTRACT

A printed circuit board according to the present invention is a printed circuit board ( 4 ) including a component mounting pin ( 1 ) made of a metal wire to connect with a semiconductor chip ( 10 ). The semiconductor chip ( 10 ) is a surface mounting type semiconductor chip having an electrode pad on its mounting surface for use in a flip-chip mounting system. The component mounting pin ( 1 ) is formed by using wire-bonding technology. This printed circuit board ( 4 ) is able to decrease malconnections or disconnection caused by a difference between the coefficients of thermal expansion of the semiconductor chip ( 10 ) and the printed circuit board ( 4 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims the benefit of U.S.application Ser. No. 11/566,862, filed Dec. 5, 2006, which claimspriority of Japanese Patent Application No. 2005-356168, filed on Dec.9, 2005. The entire content of each of these applications isincorporated herein by reference to the extent that such incorporationdoes not create an issue of new matter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to printed circuit boards, andmore particularly to a printed circuit board with a conductive componentmounting pin.

2. Description of the Related Art

[Patent Document 1]: Japanese Patent Laid-Open Publication No.2005-183466 “Multilayer Printed Circuit Board” (published on Jul. 7,2005)

The Background Art of the Patent Document 1 has described a flip-chipmounting system printed circuit board using suitable technology such assolder bump in which a solder resist layer 70 is formed on an upperlayer of a via hole 160 and a conductor circuit 158, bumps 76U and 76Dbeing formed on the via hole 160 and the conductor circuit 158 throughan opening portion 71 of the solder resist layer 70. An IC (integratedcircuit, not shown) chip may be electrically connected to the printedcircuit board by C4 (flip-chip) mounting.

However, the above Patent Document 1 fails to mention a printed circuitboard with a component mounting pin disclosed in the present invention.

SUMMARY OF THE INVENTION

On the other hand, as an integration degree of semiconductor apparatusis increasing more in recent years, a chip size thereof also is becomingenormous. If an electronic device in the mounting state in which anelectrode pad of an electronic component (e.g. semiconductor chip) of agigantic size and a land of a printed circuit board are soldered isexposed to rise and fall of an ambient temperature, then it isunavoidable that a soldered portion will be broken due to a differencebetween coefficients of thermal expansion of the electronic componentand the printed circuit board.

Therefore, a demand of developing a printed circuit board in whichmalconnections or disconnections caused by a difference between thecoefficients of thermal expansion of the electronic component and theprinted circuit board can be decreased even when a highly-integratedsemiconductor chip is mounted thereon has increased so far.

In view of the aforesaid aspects, an object of the present invention isto provide a printed circuit board in which malconnections ordisconnections caused by a difference between the coefficients ofthermal expansion of an electronic component and a printed circuit boardcan be decreased even when a highly-integrated electronic component(e.g. semiconductor chip) is mounted thereon.

A printed circuit board of the present invention includes a componentmounting pin made of a conductive material to connect with an electroniccomponent.

Further, in the printed circuit board, said component mounting pin maybe formed of a metal wire.

Further, in the printed circuit board, said electronic component may bea surface mounting type semiconductor chip having an electrode pad onits mounting surface for use in a flip-chip mounting system.

Further, in the printed circuit board, said component mounting pin ismade of a material with suitable properties such as flexibility,elasticity and pliability.

Further, in the printed circuit board, said component mounting pin maybe made of a material with low electric resistance.

Further, in the printed circuit board, said component mounting pin maybe formed by wire bonding technology.

Further, in the printed circuit board, said component mounting pin maybe formed as a pin of any shape selected from a group of pin shapes of avertical S-like pin, a horizontal S-like pin, a curved pin, a loop-likepin, a spiral pin, a spring-like pin, a circular pin and an ellipticpin.

Further, in the printed circuit board, said component mounting pin maybe coated with a protective coating.

Further, an electronic device comprising:

a printed circuit board with a component mounting pin; and

an electronic component, wherein said component mounting pin is urgedagainst an electrode pad of said electronic component.

Further, an electronic device of the present invention comprises: aprinted circuit board with a component mounting pin; and an electroniccomponent, wherein said component mounting pin is connected to anelectrode pad of said electronic component by solder-joint through asolder bump.

Further, in the an electronic device, said component mounting pin may bea mechanical element capable of absorbing mechanical energy applied toeither of or both of a semiconductor apparatus and a printed circuitboard through elasticity or deformation.

Further, in the electronic device, said printed circuit board may befixed to a case of said electronic device.

Further, in the an electronic device, said printed circuit board andsaid electronic component may be fixed to each other by adhesive.

Further, a method of manufacturing a printed circuit board with acomponent mounting pin of the present invention comprises the steps of:(a) a step for conveying a metal wire onto an electrode land of aprinted circuit board attached to a suitable positioning apparatus; (b)a step for recognizing a land bonding point of said printed circuitboard; (c) a step for compression-bonding and joining a tip end of ametal wire to said land bonding point; (d) a step for looping said metalwire; (e) a step for cutting said metal wire; (f) a step for forming aball by fusing a tip end portion of said cut metal wire; and (g) a stepfor moving a metal wire to the next land of said printed circuit board.

Further, in the method of manufacturing a printed circuit with acomponent mounting pin, said steps (a) to (g) may be executedrepeatedly.

Further, in the method of manufacturing a printed circuit with acomponent mounting pin, said step (c) may be executed by usingthermocompression bonding system and ultrasonic waves at the same time.

According to the present invention, a printed circuit board may beprovided in which malconnections or disconnections caused by adifference between the coefficients of thermal expansion of anelectronic component and a printed circuit board can be decreased evenwhen a highly-integrated electronic component is mounted thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing part of an arrangement of a printed circuitboard with a component mounting pin;

FIG. 2A is a diagram showing a method of mounting an electronic devicein which a component mounting pin of a printed circuit board is urgedagainst an electrode pad of a semiconductor chip;

FIG. 2B is a diagram showing a method of mounting an electronic devicein which a component mounting pin of a printed circuit board isconnected to an electrode pad of a semiconductor chip by solder-jointthrough solder bump;

FIGS. 3A to 3F are respectively diagrams to which reference will be madein explaining various shapes available for the component mounting pin ofthe printed circuit board; and

FIGS. 4A to 4F are respectively diagrams showing respective steps of amethod of manufacturing a printed circuit board with a componentmounting pin.

EXPLANATION OF REFERENCE NUMERALS

1: component mounting pin, 2: insulating layer, 4: printed circuitboard, 5: land, electrode land, 6: filled via, 10: semiconductor via,11: pad, electrode pad, 12: solder bump, 21: electric torch, 22: ball,23: capillary, 24: clamper, 25: metal wire, 26: spool, 27: air tension,28: position detecting camera

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A printed circuit board with a component mounting pin according to theembodiments of the present invention will be described below in detailwith reference to the drawings. In the following drawings, identicalelements and parts are denoted by identical reference numerals andtherefore need not be described.

[Printed Circuit Board with Component Mounting Pin]

FIG. 1 of the accompanying drawings is a diagram showing part of anarrangement of a printed circuit board with a component mounting pin. Asshown in FIG. 1, a printed circuit board 4 includes a conductivecomponent mounting pin 1 to connect with an electronic component, e.g. asemiconductor chip (not shown). This component mounting pin 1 can beformed by using wire bonding technology, for example.

The printed circuit board with the component mounting pin according tothe embodiment of the present invention is characterized in that acomponent mounting pin is formed on an electrode land of a printedcircuit board in advance, the component mounting pin being electricallyconnected to the electrode pad of a semiconductor chip in a surfacemounting fashion (i.e. two-dimensional mounting: mounting in which ajoint member in flip-chip mounting system is changed from solder topin).

The printed circuit board 4 with the component mounting pin 1 ischaracterized by the conductive component mounting pin 1 electricallyconnected to an electrode land (outermost layer conductor) 5.Alternatively, the electrode land 5 may be formed on a filled via-hole6. A rest of arrangement of the printed circuit board 4 can be changedfreely. Since the embodiment of the present invention is characterizedby the outermost layer conductor, the printed circuit board 4 iscomposed of an insulating layer 2 on which the outermost layer conductor5 is formed and other layer 3 formed of a predetermined insulating layerand a conductor layer and hence the insulating layer 2 and other layer 3will be explained separately in order to understand the presentinvention more clearly. It should be noted that a desired solder resistlayer may be formed on the upper surface of the insulating layer 2.

One end of the component mounting pin 1 is connected electrically to theelectrode land 5 and the other end thereof is erected from the printedcircuit board 4. The component mounting pin 1 may be coated with adesired conductive protecting coating (not shown). The printed circuitboard 4 is connected to a semiconductor apparatus (not shown) throughthis component mounting pin 1.

The component mounting pin 1 is made of a material having suitableproperties such as flexibility, elasticity and pliability and the like.Preferably, the component mounting pin 1 should be made of a materialwith low electric resistance in addition to flexibility, elasticity andpliability. Typically, the component mounting pin 1 may be formed of ametal wire.

FIGS. 2A and 2B are respectively diagrams showing methods of mountingelectronic devices including the printed circuit board 4 with thecomponent mounting pin 1 and a semiconductor chip 10. The formerelectronic device shown in FIG. 2A and the latter electronic deviceshown in FIG. 2B are different from each other in that while thecomponent mounting pin 1 is urged against an electrode pad 11 of thesemiconductor chip 10 as shown in FIG. 2A, the component mounting pin 1is solder-connected to the electrode pad 11 of the semiconductor chip 10by using a pin solder bump 12 as shown in FIG. 2B.

In the electronic device shown in FIG. 2A, the component mounting pin 1of the printed circuit board 4 electrically contacts with the electrodepad 11 formed on the semiconductor chip 10 to maintain electricconnection. The printed circuit board 4 and the semiconductor chip 10may be fixed to each other by any method. For example, both of theprinted circuit board 4 and the semiconductor chip 10 may be fixed to acase of an electronic device, although not shown. Alternatively, theprinted circuit board 4 and the semiconductor chip 10 may both be fixedto each other by using adhesive such as resin.

The mounting structure shown in FIG. 2A is characterized in that themember lying between the semiconductor device 10 and the printed circuitboard 4 to connect them is varied from the related-art solder bump tothe component mounting pin 1. Since the component mounting pin 1 is madeof the material with suitable properties such as flexibility, elasticityand pliability, it can ensure electric connection between thesemiconductor device 10 and the printed circuit board 4 when beingpressed against the electrode pad 11. Further, it is to be understoodthat the component mounting pin 1 might be a mechanical element toabsorb force (mechanical energy) applied to either of or both of thesemiconductor device 10 and the printed circuit board 4 by elasticity ordeformation. Hence, the component mounting pin 1 is able to decreasemalconnections or disconnections caused by a difference between thecoefficients of thermal expansion of the semiconductor device 10 and theprinted circuit board 4.

Further, since the component mounting pin 1 is very short in length,there can be obtained excellent electric characteristics from astandpoint of matching of a characteristic impedance Z.sub.0 and alsofrom a standpoint of increasing a propagation speed of an electricsignal. Similarly, when the component mounting pin 1 is formed of amaterial with low electric resistance, it is possible to avoid uselessvoltage drop. For example, a component mounting pin might be made of Cu(copper), Au (gold), Ag (silver) or alloy of them. Alternatively, acomponent mounting pin might be a component mounting pin which issurface-finished by these metals.

Further, since the component mounting pin 1 is erected at its other endfrom the printed circuit board 4 as described above, it can be enclosedwith the air to thereby increase a speed at which a signal istransmitted. Furthermore, when the component mounting pin 1 mechanicallycontacts with the electrode pad 10 of the semiconductor chip 10 by forceof repulsion, it is possible to maintain satisfactory electricconnection between the semiconductor chip 10 and the printed circuitboard 4.

Furthermore, the printed circuit board 4 with the component mounting pin1 according to the embodiment of the present invention is characterizedby the component mounting pin 1 in electric contact with the electrodeland 5 and a rest of the printed circuit board 4 can be changed freely.Hence, the present invention can be applied to other suitable circuitboards such as a large printed wiring board and a coreless printedcircuit board that tends to warp. Further, since the semiconductor chip10 and the printed circuit board 4 are connected together not bysoldering but by mechanical contact of the component mounting pin 1, theembodiment of the present invention has a merit that a thermal budgetduring a reflow process ant others will not be left.

FIG. 2B is a diagram showing a mounting structure in which electricconnection can be maintained by connecting the component mounting pin 1of the printed circuit board 4 and the semiconductor chip 10 viasoldering. As shown in FIG. 2B, a desired solder bump 12 may be providedat the tip end of the component mounting pin 1 of the printed circuitboard 4 and in the state in which the component mounting pin 1 isbrought in electric contact with the semiconductor chip 10, thecomponent mounting pin 1 and the electrode pad 11 of the semiconductorchip 10 may be connected by soldering through solder reflow technology.Furthermore, if requested, the printed circuit board 4 and thesemiconductor chip 10 might be fixed to each other by theabove-mentioned methods.

FIGS. 3A to 3F are respectively diagrams to which reference will be madein explaining various shapes available for the component mounting pin 1.The component mounting pin 1 is made of the material with suitableproperties such as flexibility, elasticity and pliability and it isurged against the electrode pad 11 of the semiconductor chip 10 as shownin FIG. 2A. In order to realize this mounting structure, the followingshapes are available for the component mounting pin 1.

FIG. 3A shows a component mounting pin 1-1 which is shaped as a verticalS-like pin. FIG. 3B shows a component mounting pin 1-2 which is shapedas a horizontal S-like pin. FIG. 3C shows a component mounting pin 1-3which is shaped like a curved pin. FIG. 3D shows a component mountingpin 1-4 which is shaped as a loop-like pin. FIG. 3E shows a componentmounting pin 1-5 which is shaped as a spiral or spring-like pin. FIG. 3Fshows a component mounting pin 1-6 which is shaped as a circular orelliptic pin. These shapes of the component mounting pin 1 areillustrated by way of example and any shape of the component mountingpin 1 can be used insofar as the component mounting pin 1 can be urgedagainst the electrode pad 11 of the semiconductor chip 10.

[Method of Manufacturing Printed Circuit Board with Component MountingPin]

A method of manufacturing a printed circuit board with a componentmounting pin will be now be described with reference to FIGS. 4A to 4Din comparison with related-art wire bonding technology.

First, the related-art wire bonding technology, e.g. nail-head bondingincludes the following steps of a step (1) for conveying a lead frame onwhich a semiconductor chip is mounted, a step (2) for recognizing theposition of a bonding pad of the semiconductor chip by a patternrecognition mechanism, a step (3) for executing bonding on thesemiconductor chip side, a step (4) for looping (shaping) of a metalwire, a step (5) for bonding the semiconductor chip on the printedcircuit board at its electrode land of the semiconductor chip adjacentarea, a step (6) for cutting the metal wire, a step (7) for fusing thetip end of the thus cut metal wire to form a ball and a step (8) formoving the metal wire to the next semiconductor chip.

In the method of manufacturing the printed circuit board 4 with thecomponent mounting pin 1 according to the embodiment of the presentinvention, the above-described steps of the step (1) of “conveyance”,the step (2) of “position recognition”, the step (5) of “bonding ontothe land of the printed circuit board”, the step (4) of “looping(shaping) of the metal wire”, the step (6) of “cutting of the metalwire”, the step of (7) “forming of the ball” and the step of (8) “movingof the metal wire” are executed, in that order.

In this case, it is to be assumed that the printed circuit board 4 inwhich the electrode land 5 is formed on the component mounting surfacehas already been fabricated. The following steps are executed by the useof this printed circuit board 4.

(a) Conveyance (See FIG. 4A):

The printed circuit board 4 is attached to a suitable positioningapparatus (not shown). As shown in FIG. 4A, a metal wire 25 is suppliedfrom a spool 26 through holes of an air tension 27, a damper 24 and acapillary 23 to the electrode land 5 of the printed circuit board 4. Atip end of the metal wire 25 is shaped like a ball 22.

(b) Position Recognition (See FIG. 4B):

The position of the electrode 5 of the printed circuit board 4 ismeasured by a bonder position recognition mechanism using a positiondetecting camera 28 and a bonding point of the electrode land 5 iscalculated.

(c) Bonding onto the Electrode Land of the Printed Circuit Board (SeeFIG. 4C):

The ball 22 of the metal wire 25 is urged against the bonding point ofthe electrode land 5 by the capillary 23 and the ball 22 is joined tothe electrode land 5 of the printed circuit board 4 by diffusion ofmetal. In this case, in order to decrease damages caused on the printedcircuit board 4 by heat, it is preferable that the step (c) should beexecuted by using thermocompression bonding system and ultrasonic wavestogether.

(d) Looping (Shaping) of Metal Wire (See FIG. 4D):

The metal wire 25 is shaped while elevating the capillary 23. The metalwire 25 should be reversed right and left and up and down in order toprovide a metal wire of a desired shape.

(e) Cutting of Metal Wire (See FIG. 4E):

The metal wire 25 is cut by the damper 24 when the capillary 23 iselevated.

(f) Forming of Ball (See FIG. 4F):

An electric torch 21 applies discharged electricity to the tip endportion of the thus cut metal wire 25 to fuse the tip end of the metalwire 25 to thereby form a ball. At this stage, the metal wire 25 maybecome available as the component mounting pin 1.

(g) Movement (Not Shown):

A metal wire is moved onto an electrode land 5 of the next printedcircuit board 4.

It is possible to manufacture a printed circuit board with a componentmounting pin by repeatedly executing the above-described steps (a) to(g) at a high speed. It should be noted that the step (f) can becanceled.

[The Others]

While the embodiments of the printed circuit board with the componentmounting pin according to the present invention have been described sofar, it is needless to say that the present invention is not limited tothose embodiments.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A printed circuit board comprising: an insulating layer; an outermostconductor layer having an electrode land, the outermost conductor layerbeing formed on the insulating layer; and a component mounting pinextending from the electrode land, wherein the component mounting pin ismade of a conductive material having a property of at least one offlexibility, elasticity or pliability such that the component mountingpin is configured to be urged against an electrode pad of an electroniccomponent by mechanical force of repulsion and not be soldering so as toelectrically connect the printed circuit board to the electroniccomponent by way of the component mounting pin.
 2. A printed circuitboard according to claim 1, wherein said component mounting pin isformed of a metal wire.
 3. A printed circuit board according to claim 1,wherein said electric component is a surface mounting type semiconductorchip having the electrode pad on its mounting surface.
 4. A printedcircuit board according to claim 1, wherein said component mounting pinis made of a material with low electric resistance.
 5. A printed circuitboard according to claim 1, wherein said component mounting pin isformed by wire bonding technology.
 6. A printed circuit board accordingto claim 1, wherein said component mounting pin is formed as a pin ofany shape selected from a group of pin shapes of a vertical S-like pin,a horizontal S-like pin, a curved pin, a loop-like pin, a spiral pin, aspring-like pin, a circular pin and an elliptic pin.
 7. A printedcircuit board according to claim 1, wherein said component mounting pinis coated with a protective coating.
 8. A printed circuit boardaccording to claim 1, wherein said component mounting pin is amechanical element capable of absorbing mechanical energy applied toeither of or both of said electronic component and said printed circuitboard through elasticity or deformation.
 9. A printed circuit boardaccording to claim 1, wherein said printed circuit board is fixed to acase of an electronic device including said printed circuit board andsaid electronic component.
 10. A printed circuit board according toclaim 1, wherein said printed circuit board and said electroniccomponent are fixed to each other by adhesive.
 11. A printed circuitboard comprising: an insulating layer; an outermost conductor layerhaving an electrode land, the outermost conductor layer being formed ona surface of the insulating layer; and a component mounting pinextending from the electrode land, wherein the component mounting pin ismade of a conductive material having a property of at least one offlexibility, elasticity or pliability such that the component mountingpin is configured to be connected to an electrode pad of a semiconductorchip of an electronic component through a solder bump such that asurface of the semiconductor chip having the electrode pad thereonopposes the surface of the insulating layer having the electrode landthereon.
 12. A printed circuit board according to claim 11, wherein saidcomponent mounting pin is formed of a metal wire.
 13. A printed circuitboard according to claim 11, wherein said electric component is asurface mounting type semiconductor chip having the electrode pad on itsmounting surface.
 14. A printed circuit board according to claim 11,wherein said component mounting pin is made of a material with lowelectric resistance.
 15. A printed circuit board according to claim 11,wherein said component mounting pin is formed by wire bondingtechnology.
 16. A printed circuit board according to claim 11, whereinsaid component mounting pin is formed as a pin of any shape selectedfrom a group of pin shapes of a vertical S-like pin, a horizontal S-likepin, a curved pin, a loop-like pin, a spiral pin, a spring-like pin, acircular pin and an elliptic pin.
 17. A printed circuit board accordingto claim 11, wherein said component mounting pin is coated with aprotective coating.
 18. A printed circuit board according to claim 11,wherein said component mounting pin is a mechanical element capable ofabsorbing mechanical energy applied to either of or both of saidelectronic component and said printed circuit board through elasticityor deformation.
 19. A printed circuit board according to claim 11,wherein said printed circuit board is fixed to a case of an electronicdevice including said printed circuit board and said electroniccomponent.
 20. A printed circuit board according to claim 11, whereinsaid printed circuit board and said electronic component are fixed toeach other by adhesive.